528 SNAKES OF CEYLON. 



of the ultimate row. Ultimate row enlarged ; the breadth of 

 its scales greater than their length. In 25 to 27 (rarely 29) 

 rows two heads-lengths behind the head, 27 to 31 (rarely 33) 

 at midbody, and 23 to 21 two heads-lengths before the vent. 

 Supracaudals : In even rows, all keeled to tail tip. Ventrals : 

 153 to 176 ; rounded. Anal : Entire. Subcaudals : 41 to 64 : 

 divided. 



Dentition. — Maxillary : Two large, canaliculate fangs 

 placed side by side. Palatine : 3 ; isodont, and placed in the 

 middle of the bone with a considerable edentulous space 

 anteriorly and posteriorly. Pterygoid : 9 or 10 ; isodont, or 

 slightly scaphiodont ; more than half the posterior part 

 edentulous. Mandibular : 12 or 13 ; strongly scaphiodont. 

 (Fig. 92.) 



Fig. 92. — Maxilla of Vipera russelli. Typical viperine maxilla. 

 Compare with colubrine maxilla of cobra Fig. 89. 



Distribution. — (a) General : Peninsular India to the 

 Himalayas.* In the north-west it extends to Sind, and in 

 the north-east to at least as far east as the Jalpaiguri 

 District. Southern Burma, Siam, Ceylon, the Andamans, and 

 Nicobars (?), Sumatra. 



* In my book, " The Poisonous Terrestrial Snakes of our British 

 Indian Dominions," I included the Eastern Himalayas within the 

 habitat of Russell's viper on the authority of Mr, Millar of Darjeeling, 

 who was a reliable observer. Fortunately, I have kept his letter, and 

 referring again to the list he gave me, I find that he included Russell's 

 viper on the authority of a friend from Kurseong. I have now no 

 hesitation in removing the Eastern Himalayas from its range of dis- 

 tribution, and feel sure that the friend mistook a large -spotted viper 

 {Trimerzsurus monticola) for Russell's viper as so many others have 

 done. 



